1. Field of the Invention
The present invention relates to a combined range finder and sight for an archery bow.
2. Prior Art
Known bow sights are disclosed in the following U.S. Pat. Nos.:
No. 2,767,472, issued Oct. 23, 1956 (Kocur); PA0 No. 2,863,325, issued Dec. 9, 1958 (Eisenberg et al.); PA0 No. 2,998,652, issued Sept. 25, 1961 (Zielinski); PA0 No. 3,056,206, issued Oct. 2, 1962 (Moore); PA0 No. 3,666,368, issued May 30, 1972 (Sprandel); PA0 No. 3,766,656, issued Oct. 23, 1973 (Westphal); PA0 No. 3,910,700, issued Oct. 7, 1975 (Sprandel); PA0 No. 4,195,414, issued Apr. 1, 1980 (Robinson); PA0 No. 4,584,777, issued Apr. 29, 1986 (Saunders); PA0 No. 4,711,036, issued Dec. 8, 1987 (Morris).
In each of the devices disclosed in the above patents, the position of a sight pin or bead is adjustable vertically along the handle section of the bow. With the bow held at arm's length, positioning the sight pin or bead at a lower level requires that the bow be moved upward to align the pin or bead with the target. Such upward movement is accomplished by swinging motion of the bow about the shoulder of the supporting arm of the archer, resulting in a greater angle of trajectory of the arrow which corresponds to a target farther from the archer. Similarly, positioning the sight pin at a higher level requires that the bow be swung downward to align the sight pin or bead with the target, corresponding to a lesser angle of trajectory for a closer target.
Some of the devices of the above patents have or are used with range finders. Known range finders utilize vertically spaced range finder pins. The apparent size of the target between the pins gives an approximation of the distance to the target. For example, a circular target of a known size or the body of an animal stalked by a game hunter may appear to fill the space between selected range finder pins at a known distance. At a lesser distance the target would appear to be larger than the spacing between the pins, and accurate aiming would require a reduced angle of trajectory which could be accomplished by selecting a higher sight pin or bead or by moving the sight pin or bead to a higher level on the handle of the bow. At a greater distance the target would appear to be smaller than the spacing between the pins, and the angle of trajectory of the arrow should be increased, which could be accomplished by selecting a lower sight pin or bead or by moving the sight pin or bead to a lower level on the handle of the bow.
The actual sighting procedure is more complicated because the archer must take into consideration cross wind and headwind or tail wind, the weight of the arrow, type of arrow (air resistance) and any other factor which would tend to alter the flight of the arrow. For example, in most of the devices disclosed in the above patents, the position of a sight pin or bead can be adjusted transversely to compensate for the arm position of the individual marksman and the effect of cross wind on the type of arrow being used.
Of the devices disclosed in the above patents, it is believed that those described in the two patents issued to Sprandel are most pertinent to the present invention because in each instance range finder pins are movable vertically relative to a bow handle (manually in the construction of U.S. Pat. No. 3,666,368 and by a motor in the construction of U.S. Pat. No. 3,910,700) and some adjustment of the spacing between the pins occurs as they are moved.